An electron in a hydrogen atom drops from the n= 3 energy level to the n=2 energy level. The energy of
the emitted photon is
A) 1.89 eV
C) 1.51 eV
B) 3.40 eV
D) 4.91 eV

Consider an ideal gas at 27.0 degrees celsius and 1.00 atmosphere pressure. imagine the molecules to be uniformly spaced, with each molecule at the center of a small cube. what is the length l of an edge of each small cube if adjacent cubes touch but don't overlap?